The invention relates to a sharpener for sharpening a cutting tool, such as a knife, the sharpener comprising a body part, a rotatable sharpening roll supported by the body part, and a first guide groove above the sharpening roll for receiving a blade of a first tool and for guiding it in relation to the sharpening roll.
Such a sharpener for sharpening household knives is commonly known. When the blade of a knife to be sharpened is placed into the groove of the sharpening roll and the blade is moved a number of times back and forth in relation to the body part of the sharpener, the sharpening roll, at the same time as it rotates, sharpens the blade of the tool. For the sharpening to be carried out correctly and for the blade to be sharpened rapidly and easily, the blade of the tool to be sharpened must be at a specific angle to the groove of the sharpening roll. To facilitate the placing of the blade to the correct angle in relation to the sharpening roll, the sharpener comprises a wedge-like guide groove above the sharpening roll for receiving the blade and guiding it to the correct angle. The guide groove keeps the blade in the correct position when the blade is moved back and forth on the sharpening roll. If the guide groove is made too wide, i.e., there is a gap that is too large between the guide groove and the blade side, it is possible that the blade to be sharpened sets inclined at a wrong angle in relation to the sharpening roll, in which case the blade to be sharpened becomes lopsided. This means that for narrow blades, a narrow guide groove must be provided.
As is understood from the above disclosure, a sharpener designed for narrow blades must have a guide groove that is narrow enough so that a wider blade, such as an axe blade, becomes tightly wedged to the walls of the guide groove and the portion of the blade to be sharpened does not reach the groove of the sharpening roll. Thus, sharpening is naturally impossible. In fact, because of this there are sharpeners with a wider guide groove for axes and wide blades than in sharpeners designed for knives. Such sharpeners for axes cannot be used without problems—for the above reasons—for sharpening knives.